Stock tires or rims are irrelevant to towing/load carrying capacity
The wheels are irrelevant on all trim levels for any purpose. The 20" TIRES have the lower load rating at 1,874 pounds. The 18" tires have a higher load rating, at 2,039 pounds.
The MINIMUM load rating of any tire or rim should be 1,800 pounds for a safety factor. The rear axle gross weight (GAWR-R) is the key here, at 3,296 pounds, regardless of trim level. That's a minimum of 1,649 pounds per wheel/tire with ZERO safety margin, hence my suggestion of 1,800 pounds minimum rating on wheel or tire.
On a wheel (rim), the load ratings are in pounds. On a tire, they are numbered. The Ascent is "102" rated tires for 20" (1,874 pounds) and "105" rated for 18" tires (2,039 pounds).
ANYWAYS...
The short version is, the rims and tires on the Ascent have nothing to do with the tow ratings. It's all the CVT and cooler.
The BASE Ascent has a tow rating of 2,000 pounds, and has no transmission cooler, and a different CVT assembly part number. It also has a different rear differential.
All named trims (Premium, Limited, Touring) have the transmission cooler and are capable of towing 5,000 pounds.
The Base and Premium Ascent have 18" wheels, with the option to get 20" wheels on the Premium.
The Limited and Touring come with 20" wheels and have no option to get anything else.
